The Proportion of Terramycin-resistant Mutants in B. Megatherium Cultures
نویسنده
چکیده
The number of terramycin-resistant mutants in Bacillus megatherium cultures, their mutation rate, and the growth rate of the wild and mutant cells have been determined under various conditions. These values are in agreement with the following equations (Northrop and Kunitz, 1957):- See PDF for Equation lambda = mutation rate, A = growth rate constant of wild cells, B = growth rate constant of mutants, See PDF for Equation equilibrium. The value of the mutation rate as determined from equation (6) agrees with that found by the null fraction method.
منابع مشابه
Adaptation of Bacillus Megatherium to Terramycin (oxytetracycline)
B. megatherium cultures contain a few cells per hundred million which are able to grow in the presence of terramycin. Growth of the other cells is inhibited by the antibiotic with the result that the resistant cells overgrow the culture. The resistant cells are present in the culture, without contact with terramycin, and are able to grow in the presence of terramycin, without further modificati...
متن کاملStudies of the Origin of Bacterial Viruses
Exposure of B. megatherium 899 to about 5 x 10(-3)M MnCl(2) for 10 minutes at 25 degrees C. results in an increase of about ten times in the proportion of phage-producing cells, terramycin-resistant cells, streptomycin-resistant cells, and phage-resistant cells. The proportion of phage-producing cells reaches a maximum in about 4 hours and that of the other cells is reached in about 8 hours.
متن کاملThe Effect of Ultraviolet and White Light on Growth Rate, Lysis, and Phage Production of Bacillus Megatherium
Cultures of megatherium 899a, growing under different conditions, were exposed to ultraviolet or white light. 1. Cultures exposed to ultraviolet light and then to white light continue to grow at the normal rate. Cultures exposed to ultraviolet light and then placed in the dark grow at the normal rate for varying lengths of time, depending on conditions, and then lyse with the liberation of from...
متن کاملStudy of Mutations in the DNA gyrase gyrA Gene of Escherichia coli
Quinolones are a large and widely consumed class of synthetic drugs. Expanded-spectrum quinolones, like ciprofloxacin are highly effective against Gram-negative bacteria, especially Escherichia coli. In E. coli the major target for quinolones is DNA gyrase. This enzyme is composed of two subunits, GyrA and GyrB encoding by gyrA and gyrB, respectively. Mutations in either of these genes cause qu...
متن کاملStudy of Mutations in the DNA gyrase gyrA Gene of Escherichia coli
Quinolones are a large and widely consumed class of synthetic drugs. Expanded-spectrum quinolones, like ciprofloxacin are highly effective against Gram-negative bacteria, especially Escherichia coli. In E. coli the major target for quinolones is DNA gyrase. This enzyme is composed of two subunits, GyrA and GyrB encoding by gyrA and gyrB, respectively. Mutations in either of these genes cause qu...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- The Journal of General Physiology
دوره 41 شماره
صفحات -
تاریخ انتشار 1957